Coil structure for electromagnetic devices.



C. H THOBDARSON.

COH. STRUCTURE FOR ELECTROMAGNETIC DEVICES.

APPLICATION FILED JUNE 30.1913.

1,215,429. Patented Feb. 13,1917.

1:113 srntrns THQ'RDARSON, OF CHICAGO, ILLIN'QIEE.

GGEL ETRUGTURE FOB ELECTROMAGNETIC DEVICES.

Specification of Letters Patent.

- January 24, 11913, Serial No. 744,001. Divided and this application filed June Patented Feb. 13, 131?.

1913. Serial No. 776,521.

Y may concern innsrrn H. Trronnnu- United States, and a in the county of Cook have invented, certain vements in Coil Strucagnetic ilevices; and I that the following is a exact description thereof,

the accompanying characters reference ch form part of the anon. This invention. relates to improvements in coil structures for transformers or other "ietic devices and the invention the matters hereinafter set forth LieL rry pointed out in the apjects of the invention is to eiiiciency' of a coil structure n el. ctro-magnetic devices to adapted, as compared to the size thereof, and to reduce the "notion.

uject of the invention is to roved means for insulating ne of the coil one from the '5 1s the structure and its capaccoz npared to known coil structures. A further object of the invention is to wide coil. vinding, made up of flat d interwound insulating strips in inleding is exposed to a cooling medium, as oil, in which the ":ii is submerged, so as to thereby enable the windings of .a. translike structure to be maintained at temperature to prevent char- J at the same time increasing the edge or edges each turn of thedown. of the coil, even when it isunit of area, and in contact with the cooling medium, relatively low and thus facilitate maintenance of a suitably low temperature in the coil structure.

A further object of the irvention is to provide a coil or winding of the character herein set forth, in which the current den-- sity is substantially directly proportionate to the cross section of the fiat wire or conductor, thereby realizing maximum conductive cfliciency of the wire.

The invention is herein shown as applied to a transformer construction, but it will be understood that it may be equally well and as eflicicntly applied to other electro magnetic dev'ces.

In the drawings:

Figure 1 is a side elevation 01 a transformer provided with a coil embodying my invention, with the casing of the transformer shown in section.

Fig. 2 is a vertical section on the line 2-2 of Fig. 1.

Fig. 3 is an enlarged side elevation of a portion of a coil embodying my invention.

Fig. 4: is a fragmentary transverse section of the coil.

The elements of the transformer in which my improved coil is herein shown as embodied may be of any preferred construc tion, and as herein shown is made like the transformer illustrated in my prior application for U, 5. Letters Patent #744,001, filed January 24, 1913, of which this application is a (llVlSlOIL As shown in the drawings, 10 designates the inclosing casing; 11 the laminated magnetic circuit structure composed of superposed thin plates of good magnetic metal, the whole being held in place or clamped together by means of bolts 12, 12, which extend through corresponding members of gle bars 14, 14 arranged in the angles be tween the sides of the magnetic Cll'Clll'u structure and the windings wound upon the magnetic structure as will hereinafter appear, certain of the bolts 12 having nuts thereon to constitute spacing means for the angle bar clamping members.

15, 15 designate the three units of the primary winding and 16, 16 the two units of he secondary winding, as the transformer construction is herein shown as organized. The units of the primary winding may be connected in series or multiple, and the units of the secondary winding may be likewise connected. Suitable insulation is provided between the primary and secondary windings, the construction and arrangement of which is shown in my aforesaid application and need not be further herein described.

The said windings of both the high and low tension coils are composed of narrow fiat ribbon wire and are alike in both the high and low tension coils, except as to the dimensions of the wires forming the same. T he present invention relates more particularly to the manner of insulating the turns of the windings from each other, in such a f .t the several turns are efficiently ineed and the structure of the coil as a whole is rendered strong and durable, while the same time making it possible to proii a coil of maximum eilicienc'y as compared to its dimensions and weight and the cost of it. production.

ihis feature the invention is embraced].v

following construction:

etween each turn. 20 of each winding is interposed two or. more thin sheets 21. 21

n insulating material, such as paper. of insulating material are usu- .de wider than the flat wires of the and therefore, extend laterally .e margins of said wires or turns, most clearly in Fig. l, so; as to prevent short circuiting of one turn other around their lateral margins. practice l have iound that a projection or the sides the insulating strips 21 bed the wires or strips 20 of one-thirty to ti i'ee-sinty-foirrths of an inch. is or transformers of the size most used. These strips of insulat-" al are made as thin as the physh conditions will permit, having regard the ordinary handling thereof and the winding of the same in the winding unit or instance, have used in high ten-- sion coils orwindings insulating sheets ess "hair one-half of one-thousandth of an rich in thickness.

l *e found that a single thickness of insular strip, as for instance, paper, is unreliable by reason of the fact'that ilaws occur in the paper and impair the insulatefi'iciency thereof, and that. to avoid such defects with a single strip of paper or insulating material, it is necessary to pro- 'vide a strip of such thickness as to render the coil structure excessively large and heavy. By using two or more thin strips of papen or -lilre material, (two being new ally sufficient) the chances offlaws in the reissue paper registering so as to produce a through opening in the superposed strips through which one turn may be short circuited the other is so small as to be negligible.

As a result of this construction and abled to produce a highly efiicient insulation between the turns of the windings, at the same time reduce the thicknessof the multiple sheet insulation as comp to a single strip heretofore used. 1 i found in practice that a coil or wincn unit of a given capacity be reduced dimensions substantially one-half that the prior construction where a single efii cient insulating sheet or st ip becween turns is employed. The construction is not only compact but is'also of less relative weight as compared to prior constructions of equal eiliciency. This is par l the fact also that the lQdU'CElOIi weight and dimensions of the coil permits o a 'corresponding reduction of the we' a'd size of the magnetic circuit structur Moreover a multi-sheet insulation is fa superior in eiiicie'ncy to any practical single sheet insulation heretofore used.

After the units are wound, they maybe treated by a suitable insulating liquid such as parai'iin, to increase the insulating sill-- ciency of the paper, and to stiffen the wind ing structure by means not to impose a coating on the edges of theturns to rially modify the interchange of heat he tween the conductor and a cooling inedi in the claims, therefore, reference to hare edges of the turns does not exclude the to the winding form, inasmuch as the pres sure difference between the inner turns is not great.

It will be observed from an inspection of Fig. 1 that the flat wire conductors are quite narrow. In practice, these conductors do not exceed five-eighths of an inch in width and may be made as narrow as onctwelfth of an. inch. 1 have found that a flat wire conductor decreases in its efficiency as a conductive medium after its width reaches to or increases beyond five-eighths of an inch. This is due, in a transformer of the character herein shown, partially to the fact that the pressure developed between adjacent windings tends to crowd the'fiow of current toward one edge of the flat 'cbnductor, or towardthe edges presented toward the'least pressure. Thus vice as a whole. Moreover, tl-iere is,

.' or about one member of a magnetic eddying currents due to in as of force passing from one other oi the magnetic clrcuit, which 3 sheet of mpairing the conductive latter a vices r as rect cu n, ea ticularly noticeable in deternating current circuit, =1 r, and in devices used in dinits where the circuit is freand closed. By making the sires narrow, 1 am enabled to mourn ethciency with minimum 1e and cost.

furthermore observed that t wire conductors nar: 1 she 9 the cross sectional onductors is maintained low r re of the side edges there- I 'ansiormer or the like, are one cooling medium, so that heat developed in the conductor ily conducted away therefrom overheating of the structure breaking down of the insulaturns of the winding. Morex. coil structure is further adapted to 1 a suitably low temperature fact that one or both edges of the winding is adapted to be coolingagent, thus providing so: c:

the winding to the cooling vantage of the construction by reason of the possibility of as wire composing the same, the 1g structure itself is relatively coil or winding structure of capacity constructed under the c, of reducing the weight of nineor other electromagnetic e i which my improved coil is emi where such transformer or 'suppoiter" at considerable inetancc on a pole. The rein; and dimensions enables the e to be made less massive, he liability o'f-the superne foundation of the pole o excessive wind pressures. antage of employing windcoils made of fiat bare wire, as described, is that the magof the winding has the efiect e wire from the insulating strips w the cooling oil to flow across fiat faces of the bare wire,

" r strip wound about a mag v of the flat conductor. This efficient interchange of heatdimension of the coil and the the strips between adjac i s than that of a. single st material oi s gnal insulatin' (M11837.

2. In electro-niagne 1c device, a w liding composed of a plurality of turns care narrow fiat wire, with two or more superimposed insulating strips between adjacent turns, said strips being of uniform thickness from edge to edge and extending at the edges thereof beyond the bare edges of the wire in a manner to expose the bare edge of each turn at the side of the winding andto insulate the bare edges of adjacentturns from each other, each insulating, strip being so thin as not to afford in its if a reliable insulation between the. turns and the combined thickness of the multiply insulation between adjacent turns being less than that of a single strip of the same material of equal insulating efficiencyn 3. An electromagnetic winding composed of a plurality of turns of narrow, fiat thin bare wire, with two or more thin insulating strips between adjacent turns, each strip be ing so thin as not to afford in itself a reliable insulation between the turnsand with the combined thickness of the strips between adjacent turns less than that of a single thickness strip of the same material of equal insulating efileiency, the bare edge of each turn of said wire being exposed at the side of the winding; and insulated from adjacent edges by said strips, and the cross section of the flat wire being small relatively to the bare exposed area the side edge thereof 4. An electro-magnetic winding composed of a plurality of turns iiat, bare, transversely continuous wire, the edges of all of the turns of which are exposed at the side of the winding, an insulating medium sepa rating the turns and lying against the bare ofuniform thickness from edge to and extending at the edge thereof laterally beyond the line of contact thereof with the fiat wire to provide means for avoiding short-cir 'uiting of adjacent turns upon each faces thereof the insulatin medium bein obher, and arranged E0 nminsainjhe edges 05: 7 the turns xposad to free access, to 311-811" th1s'26thdaybf June, 1913 velaping cooling medmzmandto Prevent 0b- 21E T Tm 1 J5] BL structlon or l'esardatmn 1n the free lnter- CH ST H HORDA change of ham; between smd edges and such Wmtnessw:

G E. DOWLE,

medium In test-11110117, whereof i have afifxed my L.

signature in the presence bf 7W0 WifimeSSQs; 

